Patent Literature 1 describes a manipulation detection device and program thereof (see paragraph [0007] of the specifications) having the object of “detecting manipulation information without utilizing a special device” (see paragraph [0006] of the specifications), and in order to achieve that objective, is a “manipulation detection device also utilizing an illuminating means and image capture means, and including a means to capture an image of the operator in a state where illuminated by the illuminating means; a means to detect the region of a specific section of the operator based on image data of the operator that is obtained by way of the image capture means; and a means to extract the shadow section from the region of a specific section of the operator that was detected; and a means to detect plural lines whose edges form a straight line (or that form a straight line at the edge), and detect points where the detected lines jointly intersect as acute angles, and to detect that intersection point as the pointing position” by the operator within a region of a specific section of the operator.
Patent Literature 2 describes an electronic pen system (see paragraph [0009] of the specifications) with the problem of “providing an electronic pen system including an electronic pen capable of parallel equivalent usage of the finger and electronic pen (see paragraph [0008] of the specifications), and as a means to resolve that problem, is an “electronic pen system containing a touch panel including a touch surface on which a touch operation is performed by the electronic pen and finger, and a position detection device to detect the electronic pen and the finger touch positions on the touch surface, and a display device to display the required image as the display screen of the touch surface, and a control device to display an image on the display device corresponding to the position detection information that is acquired from the position detection device; and characterized in that the control device includes an instruction object judgment means to judge whether the position detection information is from the electronic pen or the finger when the position detection information is received from the position detection device, a first control means to perform the specified pen input processing corresponding to touch operation by the electronic pen, and a second control means to perform the specified finger input processing corresponding to touch operation by the specified finger input; and further executing the first control means for pen input processing and the second control means for finger input processing in parallel.